feat: add user-defined command aliases via ~/.bernstein/aliases.yaml

src/bernstein/cli/aliases.py

@@ -4,11 +4,18 @@
 
 Provides a Click Group subclass that resolves short aliases to
 full command names, plus a registry of built-in aliases.
+User-defined aliases can be loaded from ``~/.bernstein/aliases.yaml``.
 """
 
 from __future__ import annotations
 
+import logging
+from pathlib import Path
+
 import click
+import yaml
+
+logger = logging.getLogger(__name__)
 
 # ---------------------------------------------------------------------------
 # Alias registry
@@ -25,6 +32,11 @@
     "i": "overture",  # init (hidden name: overture)
 }
 
+# Track which aliases are user-defined (populated at load time)
+_USER_ALIASES: dict[str, str] = {}
+
+_USER_ALIASES_PATH = Path.home() / ".bernstein" / "aliases.yaml"
+
 
 def get_alias(name: str) -> str | None:
     """Return the full command name for an alias, or None.
@@ -43,6 +55,31 @@ def get_all_aliases() -> dict[str, str]:
     return dict(ALIASES)
 
 
+def _load_user_aliases() -> dict[str, str]:
+    """Load user-defined aliases from ~/.bernstein/aliases.yaml."""
+    if not _USER_ALIASES_PATH.is_file():
+        return {}
+    try:
+        with open(_USER_ALIASES_PATH) as f:
+            raw: object = yaml.safe_load(f) or {}
+        data: dict[str, object] = raw if isinstance(raw, dict) else {}
+        return {str(k): str(v) for k, v in data.items() if isinstance(k, str) and isinstance(v, str)}
+    except Exception:
+        logger.debug("Failed to load user aliases from %s", _USER_ALIASES_PATH, exc_info=True)
+        return {}
+
+
+def _merge_aliases() -> None:
+    """Merge user aliases into the global registry (user overrides built-in)."""
+    global _USER_ALIASES
+    _USER_ALIASES = _load_user_aliases()
+    ALIASES.update(_USER_ALIASES)
+
+
+# Call at module load time
+_merge_aliases()
+
+
 class AliasGroup(click.Group):
     """Click Group that resolves short aliases to full command names.
 
@@ -92,6 +129,7 @@ def aliases_cmd() -> None:
     table = Table(title="Command Aliases", show_header=True, header_style="bold cyan")
     table.add_column("Alias", style="green", width=10)
     table.add_column("Command", style="white", width=20)
+    table.add_column("Source", style="dim", width=10)
     table.add_column("Description", style="dim")
 
     _descriptions: dict[str, str] = {
@@ -107,7 +145,8 @@ def aliases_cmd() -> None:
 
     for alias, command in sorted(ALIASES.items()):
         desc = _descriptions.get(alias, "")
-        table.add_row(alias, command, desc)
+        source = "[cyan]user[/cyan]" if alias in _USER_ALIASES else "[dim]built-in[/dim]"
+        table.add_row(alias, command, source, desc)
 
     console.print(table)
     console.print("\n[dim]Usage: bernstein <alias> [options][/dim]")